Shonisaurus

Shonisaurus was the size of an adult Sperm Whale. It is the second largest known icthyosaur. Shonisaurus had teeth only at the front of its mouth.

There is another icthyosaur that is even bigger than the Shonisaurus; it doesn't have a name yet. The biggest icthyosaur (I'd like to call it, Megacephalosaurus) was 75 feet and its head was bigger than an entire Orca. If it were alive today, it would be big enough to eat an entire Orca.